Well-load alleviator for pumping units



June 25, 1963 J. F. EATON WELL-LOAD ALLEVIATOR FOR PUMPING UNITS Filed July 6, 1961 INVENTOR Job/7 /1- fafa/7 BY hwy/2f.

ATTORNEY point.

United States Patent "O i Patented June 25, 1963 `3,094,879 WELL-LOAD ALLEVI 'TOR FOR PUMPING UNITS John F. Eaton, Tulsa, Okla., .assignor to Bethlehem Steel Company, ar corporation of Pennsylvania Filed July 6,1961, Ser. No. 122,139 7 Claims. (Cl. 74-41) This invention relates generally to` an arrangement for cushioning the` loads of a pumping unit Vand more specilically to a wellload alleviator comprising a compressible medium and positioned to'form an integral part of the pumping unit.

It is known -that the use of acompressible medium on the well rod string results in numerous advantages including the reduction of peak well rod loads and rodfailures, a cushioning of the vibrations` resulting from the pumping unit mechanical linkage and/ or the well rod connections, proteetion of the pumping unit drive means by the absorption of vibration and peak wellloads, a decrease in well rod impact loads and a general increase in pumping efficiency. The present inventionprovides the above advantages and in addition provides an integrated structure Iwhich can e'iciently sustain the operating loads. This is accomplished by providin-g a pumping unit cornprisin-g a well load alleviator yframe having one Vend pivotally connected to the walkingbeam-and the other end yadapted to be oscillated by the pumping unit drive means. A suitable compressible medium is positioned between the alleviator frame and the walking beam. A damping cylinderpivotahy attached to the walking beam and ,the alleviator frame .controls rebound due `tothe compressible medium. The alleviator frameand Walking beam ,are so positionedfas to allow adequate space for the compressible medium in proximity to the drive means .load vapplication Thus the load transmitted tothe compressible medium is not unduly multiplied.

An object of this invention is to provide a pumping unit which-includes av well load alleviator as an integral part thereof and arranged to *eiciently sustainV and cushion the operating loads.

Still other and further objects of this invention will be apparent yfrom the specification and claims.

In the drawings:

FIG. l is a top view of FIG. Q..

FIG. 2 is a fragmental side view of the pumping unit.

FIG. 3 is a sectional view taken on lthe line 3-3 of FIG. 2.

With reference to the drawings, the pumping unit comprises a Samson post (partially shown) having ya walking beam 111 pivotally attached thereto by means of saddle bearing 12. Saddle bearing y12 permits the walking beam 11 to oscillate relative to the samson post 10 `as indicated by arrows E13. Fixed to one end of the walking beam 1.1 is a horsehead 14 to which is connected in the usual manner the well rods (not shown). Adjacent the other end of the walking beam 11 and secured to the underside there-of by means of bolts 15 is a lower extension member 16 1which extends in the same longitudinal plane as the walking bea-m 11. A plurality of transverse members 17 have their approximate longitudinal midpoints attached by weld areas 18 to the underside of lower extension member 16 and extend a substantial distance beyond the sides of the walking beam 1:1 and at a right angle thereto. Channel members 19, *19 fare iixed to the ends ofthe transverse members 17 by means of weld areas 20 and extend parallel to the Walkin-g beam "11. Spaced within channel members 19, 19 `are a plurality of transverse spacers 21 which divide the channels into .a plurality of compartments -for the reception of coil springs 22. In summary, the end of the walking beam 11 opposite the horsehead 14 has fixed thereto an .arrangement for supporting a compressible medium, eg. coil springs 22, comprising a lower extension member 16, a plurality of transverse members 1'7, and channel members 19, 119 divided by transverse spacers 21 for receiving coilA springs 22. It should be yunderstood that other structural arrangements of the walking beam i111 could be used to support the coil springs 22.

Pivotally attached to the walking'beam {1'1 is an alleviator lframe, generally ,indicated vas y24, comprising arm members 25, 25 and a tail bearing 'base member 26. An alleviator bearing assembly 27 attached to the end of each arm member 25 by means of bolts 28 and rotably mounted on alleviator `frame bearing shaft 23 suitably mounted on the underside of the Walkingbeam 11 and extending on both sides thereof pivotally connects the arm members 25, '25 of the alleviator frame 24 to the walking beam 11. As sho-wn iniFIGURES 1 .and 2, arm members 25, 25 Aare positioned adjacent the sides of walkinglbeam 11 and are connected to tail bearing base member 26 by integral diagonal .members 25a. A,Positioned between the Varm members 25, 2'5 of alleviator frame 24 and channel members 19, 19 of the walking beam -11 are ,a plurality of coil springs 22. Cylindrical sections 29 fixed -to the underside ofthe arm members 25,25 -twithin `the coil springs 22, and cooperate with spacers 21xed in channel members 19, 19 .toproperly position the coil springs 22. It is evident that the coil ysprings22 could be replaced by some other compressible medium such yas rubber pads.

This arrangement per-mits the positioning of a plurality of coil springs22 or other compressible medium adjacent the endl of the walking beam 11 and ar-m members 25, 25 and in proximity to the drive end of the pumping unit. Thus, the force transmitted to the coil springs 22 is not unduly multiplied.

FIGS. 1 "and 2 show the armmembers 25, 25 of .the -alleviator fframe 24-pivotally connected to .the walking beam 11 at a point on the wal'kingbeam 1f1 whichis 1ocated between the Samson post 10 or saddle bearing 12 and the horsehead 14 or well load end of the walkingbeam lil. For longer walking beams, it may be `desirable to pivotally connect the alleviator frame24 to the walking beam 11 at a point on the walking beam 11 which located between the Samson post 10 and the drive end.(end opposite horsehead 14) of the walking beam 11.

Mounted on the tail-bearing base member 26 of the -alleviator frame 24 is a tail bearing 30 to which is pivotally attached `a crossbeam 3-1. Pitmans 32, 312 (partially shown) have one end pivotally connected to the ends of cross beams =31 and the other end connected to the usual motor `means for supplying an oscillatory motion to the alleviator frame 24, las indicated by arrows 39.

Suspended between and pivotally attached -to the walking beam 11 and tail bearing plate member l26 of allevilator `frame 24 is a damping cylinder 33. Pads 34 having an aperture for receiving pin 35 which passes through the end of -the damping cylinder piston rod 36 are iixed -to the walking beam 11, and pads 37 having an aperture for receiving pin 38 which passes through the end of the damping cylinder body are fixed to tail bearing base member 26. The damping cylinder 33 includes bypass and control valves (not shown) arranged to olfer minimum resistance to the downward movement of the alleviator frame 24 and a variable resistance to the upward movement of the alleviator 'frame 24. Thus, the damping cylinder supplies a force which tends to absorb any rebound due to the compressible medium. This function of the damping cylinder is especially useful when extremely rough operating conditions are encountered and the load on the pumping unit tluctuates rapidly. It is evident that other means may be provided to control the rebound of coil springs 22.

In operation, pitmans 32, 32 actuated by the usual drive means impart an oscillatory motion to alleviator frame 24 as indicated by arrows 39. This motion Yof alleviator frame Z4 pivotally attached to Walking beam 111 by means of alleviator frame bearing shaft 23 causes a -force to be passed through coil springs Z2 to the Walking beam 111 which in lturn oscillates about saddle bearing 12. Since Ithe well load applied at the horsehead varies according to lthe rise :and fall of the well rods and other conditions including impact or shock, the resistance force offered by the walking beam 1=1 to the oscillatory motion imposed upon'it by the alleviator frame y24. varies. This variation in the resistance force offered by walking beam 11 causes the coil springs to compress or expand. This compres- -sion or expansion of the coil springs 22 allows the well rod (not shown) connected to horsehead 1-4 of Walking beam 1,1 to lead or lag the frequency imposed by the pitrn'ans 32, 32 to alleviator -frame 24. This ability of the Well rods to lead or lag the yfrequency of oscillation imposed by the pumping unit drive means on the well load alleviator 'frame 24 results in the cushioning of forces in the well rods, the absorption of shocks due to well conditions such as gas-lock or duid-pound and an overall increase in pumping eiciency.

Although I have described my invention hereinabove l in considerable detail, I do not wish to be limited narrowly to the exact and specific particulars disclosed, but I may lalso use such substitutes, modiiications, or equivalents as are included within the scope and spirit of the n I invention or pointed out in the appended claims.

I claim:

l. A well load alleviator for a pumping unit comprising a Walking beam pivotally mounted on a 'Samson post and including a transverse member adjacent one end and extending on both sides thereof, an alleviator -frame having one end pivot-ally attached to said Walking beam and extending on both sides thereof, a compressible medium between said transverse member and said alleviator frame,

and means adapted to provide an oscillatory motion to 3. A well load :alleviator Ifor a pumping unit comprising a walking beam pivotally mounted on .a Samson post and including a transverse member adjacent one end and extending on both sides thereof, an alleviator frame including a base member land ar-m members, the ends of said arm members being pivotally attached to said walking beam, a plurality of coil springs arranged between said transverse member and said arm members, means connected to said base member :and adapted lto provide an oscillatory motion to said alleviator trame.

4. A Iwell load alleviator for a pumping unit comprising la Walking beam pivotally mounted on a samson post and including a transverse member adjacent one end thereof, said transverse member extending a substantial distance beyond the sides of said Walking beam, an alleviator frame including a base member and arm members pivotally attached to said Walking beam, said `arm members being positioned =on both sides of said Walking beam and located substantially above said transverse member, a plurality of coil springs positioned between said arm members and said transverse member, and means connected to said base member Iand adapted to provide an oscillatory motion to said alleviator frame.

5. A Well load alleviator for a pumping unit as described in claim 4 and including .a :damping cylinder pivotally attached to said walking beam and said alleviator frame `and so arranged as to control the force exerted by said coil springs.

6. A well load alleviator for a pumping unit comprising a walking beam pivotally attached to a Samson post and including a lower extension member having a plurality of transverse members attached thereto, said transverse members extending .a substantial distance beyond the sides of said Walking beam, channel members connecting theends of said transverse members and having a plurality of coil springs arranged thereon, an alleviator frame including arm members connected at one end by a base member, said Iarm members being in contact with said coil springs and pivotally attached at the other end to said Walking beam, and means connected to said base member Iand adapted to provide an oscillatory motion to -said alleviator frame.

7. A well load alleviator as described in claim 6 and including a damping cylinder pivotally attached to said Walking beam andsaid alleviator -frame and adapted to control the force exerted by said coil springs.

References Cited inthe le of this patent UNITED STATES PATENTS 1,122,255 Copeland Dec. 29, 1914 

1. A WELL LOAD ALLEVIATOR FOR A PUMPING UNIT COMPRISING A WALKING BEAM PIVOTALLY MOUNTED ON A SAMSON POST AND INCLUDING A TRANSVERSE MEMBER ADJACENT ONE END AND EXTENDING ON BOTH SIDES THEREOF, AN ALLEVIATOR FRAME HAVING ONE END PIVOTALLY ATTACHED TO SAID WALKING BEAM AND EXTENDING ON BOTH SIDES THEREOF, A COMPRESSIBLE MEDIUM BETWEEN SAID TRANSVERSE MEMBER AND SAID ALLEVIATOR FRAME, AND MEANS ADAPTED TO PROVIDE AN OSCILLATORY MOTION TO THE OTHER END OF SAID ALLEVIATOR FRAME. 